// JavaScript Document

var divs = document.getElementsByTagName("div");

////////////////////////////////////////////////////////////////////////////////////////////////////
//////////
//////////	Auto-crossfading background images
//////////
//////////	Last modified: 2010/10/21
//////////
////////////////////////////////////////////////////////////////////////////////////////////////////

var background_images = new Array();
var background_image_index = 0;
var background_timeout = null;
var background_interval = null;

var crossfade_delay_seconds = 5;

function autoadvance_background() {
	background_image_index++;
	if (background_image_index >= background_images.length) {
		background_image_index = 0;
	}
	
	if (background_interval === null) {
		background_interval = setInterval(crossfade_background, 30);
	}
	
	background_timeout = setTimeout(autoadvance_background, crossfade_delay_seconds * 1000);
}

function crossfade_background() {
	var intervalNeeded = false;
	
	for (i = 0; i < background_images.length; i++) {
		var image;
		
		image = background_images[i];
		
		var alpha;
		
		if (i == background_image_index) {
			if (image.style.display != "block") {
				image.style.display = "block";
				setAlpha(image, 0.00);
			}
			alpha = getAlpha(image);
			if (alpha < 1.00) {
				intervalNeeded = true;
				
				alpha += 0.10;
				setAlpha(image, alpha);
			} else {
				clearAlpha(image);
			}
		} else {
			if (image.style.display == "block") {
				alpha = getAlpha(image);
				if (alpha > 0.00) {
					intervalNeeded = true;
					
					alpha -= 0.10;
					setAlpha(image, alpha);
				} else {
					clearAlpha(image);
					image.style.display = "none";
				}
			}
		}
	}
	
	if (!intervalNeeded) {
		clearInterval(background_interval);
		background_interval = null;
	}
}

for (i = 0; i < divs.length; i++) {
	if (divs[i].className == "background-image") {
		background_images[background_images.length] = divs[i];
	}
}
if (background_images.length > 0) {
	background_images[0].style.display = "block";
	
	background_timeout = setTimeout(autoadvance_background, crossfade_delay_seconds * 1000);
}